Performance of the systemic lupus erythematosus risk probability index in a cohort of undifferentiated connective tissue disease

We sought to evaluate the performance of the systemic lupus erythematosus (SLE) Risk Probability Index (SLERPI) for identification of SLE in a large cohort of patients with undifferentiated connective tissue disease (UCTD). The SLERPI was applied in a cohort of patients who met classification criteria for UCTD and did not fulfill any classification criteria for other defined CTD including SLE. Patients with a SLERPI score of > 7 were "diagnosed" as SLE. Patients diagnosed with SLE and those not, were compared in terms of disease characteristics and index parameters. A total of 422 patients with UCTD were included in the study. Median (IQR) SLERPI was 4.25 (2.5) points, while 39 (9.2%) patients had a SLERPI score >7 and were diagnosed as SLE. Patients with younger age (p = 0.026) and presence of malar rash (p